We investigated stratigraphic changes in mollusk death assemblages and geochemistry in sediment cores from four seagrass beds and one unvegetated site in the Gulf of Guanahacabibes (GG), NW Cuba. There was a transition from mangrove to seagrass beds, associated with sea level rise ∼6000 years ago. Sediment accumulation rates during the last century showed a general rise, but increased sharply after ∼1980, likely because of human activities. The GG displayed overall high mollusk γ-diversity, and our estimate of 189 species is biased toward the low end. High β-diversity was driven by inter-site differences in grain size, vegetation cover, and nutrient input. Spatial heterogeneity within the basin influenced downcore abundance and diversity metrics, highlighting the influence of local drivers. Herbivorous gastropods dominated in seagrass beds and suspension feeder bivalves were dominant on sandy bottom. In the top parts of cores, species richness declined at two sites that were subject to high, human-mediated bulk sedimentation rates and eutrophication. Conservation measures are needed to preserve this hotspot of marine diversity.

我们调查了古巴西北部瓜纳哈比贝斯湾 (GG) 的四个海草床和一个无植被地点的沉积岩芯中软体动物死亡组合和地球化学的地层变化。大约 6000 年前，红树林向海草床过渡，与海平面上升有关。上个世纪的沉积物积累率普遍上升，但在 1980 年后急剧增加，可能是由于人类活动。GG 显示出整体较高的软体动物 γ 多样性，我们对 189 个物种的估计偏向于低端。高 β 多样性是由颗粒大小、植被覆盖和养分输入的站点间差异驱动的。盆地内的空间异质性影响了下核丰度和多样性指标，突出了当地驱动因素的影响。草食性腹足动物在海草床中占主导地位，而悬浮饲养的双壳类在沙质底部占主导地位。在岩心的顶部，两个地点的物种丰富度下降，这两个地点受到人类介导的大量沉降率和富营养化的影响。需要采取保护措施来保护这个海洋多样性的热点。